What is the current situation with nested sortables?

I came across this post which was posted last year and talks of making
it into UI but I don't know where the conversation led. As far as I'm
aware its not in the latest UI so could someone update me as I really
need this functionality.
I've made a nested sortable tree - http://www.mail-archive.com/jquery-ui@googlegroups.com/msg00518.html